Properties of a Transport Instrument for Measuring Psychological Impacts of Delay on Commuters, Mokken Scale Analysis

This study assessed the validity of instrument including various negative psychological and physical behaviors of commuters due to the public transport delay. Instruments have been mostly evaluated by parametric method of item response theory (IRT). However, the IRT has been characterized by some restrictive assumptions about the data, focusing on detailed model fit evaluation. The Mokken scale analysis (MSA), as a scaling procedure is a non-parametric method, which does not require adherence to any distribution. The results of the study show that in most regards, our instrument meets the minimum requirements highlighted by the MSA. However, the instrument did not adhere to the minimum requirements of the “scalability” for two variables including “stomach pain” and “increased heart rate”. So, modifications were proposed to address the violations. Although MSA technique has been used frequently in other fields, this is one of the earliest studies to implement the technique in the context of transport psychology.

Python app for drawing Bode diagram asymptotes of transfer function for minimum and non-minimal phase systems

The purpose of this article is to introduce an application to draw the asymptotes of Bode diagram module and phase from each constituent elementary factors of any transfer function for minimum and non-minimal phase systems without transport delay. The Bode diagram is the most used tool in the frequency response method. Python was used to program the application to perform the operations as well as the Qt5 Design for the simple graphical interface for the application and all this in the Linux operating system. The application purpose is to assist students in learning the concept and drawing of Bode diagram. For students the non-minimum phase system Bode diagram is more difficult to draw than a minimum phase system due to the presence of zeros and/or poles on right half of s-plane. The phase asymptotes of a quadratic factor was closest to the real phase curve around the corresponding undamped natural frequency and this can be observed in the example showed in this article. This example must be used as a help and not a simply to solve a problem.

ADAPTATION OF THE TRAFFIC SIGNAL CONTROL DESIGN METHOD TO A HAMBURGER ROUNDABOUT

Introduction: Currently, hamburger roundabouts with traffic signal control have limited application in the road networks of large cities. During analysis of scientific and technical literature, we established that it does not contain any systematic information on the possibility of their application or methods to determine their parameters. Purpose of the study: We aimed to adapt Webster’s method of traffic signal design to hamburger roundabouts with traffic signal control, considering the specifics of traffic management. Methods: In the course of the study, we used methods of traffic analysis and simulation in the field-proven Aimsun software, recommended for use by scientific and technical literature on traffic management. We also assessed the efficiency of the adapted method by using the simulation results and comparing average transport delays at intersections considering the standard and adapted methods. Results: It was established that the adapted method of traffic signal cycle design reduces the average transport delay by 28% on average.

Relay Identification Using Shifting Method for PID Controller Tuning

The aim of this study was to present a relay shifting method for relay feedback identification of dynamical systems suitable for PID controller tuning. The proposed technique uses a biased relay to determine frequency response points from a single experiment without any assumptions about a model transfer function. The method is applicable for open-loop stable, unstable, and integration processes, even with a delay, and regardless of whether they are oscillating or non-oscillating. The core of this technique was formed by the so-called relay shifting filter. In this study, the method was applied to a parameter estimation of a second-order time-delayed (SOTD) model that can describe, with acceptable accuracy, the dynamics of most processes (even with a transport delay) near the operating point. Simultaneously, a parameter setting for the PID controller was derived based on the model parameters. The applicability of the proposed method was demonstrated on various simulated processes and tested on real laboratory apparatuses.

Bullwhip Effect – Logistic Stability Examination in Serial and Arborescent Topologies with Demand Uncertainty and Delay

The paper analyzes the formation of the bullwhip effect in logistic systems as a significant threat to preserving stability in the face of non-negligible goods transport delay and uncertainty of demand and stock records. The popular order-up-to policy is selected as the method governing the goods flow. A dynamic model of entity interaction is constructed and examined, first, analytically, then in numerical tests for various scenarios of practical significance, e.g., a supply chain with external and local demand signals or real-world European goods distribution system. It has been found that the order-up-to policy does not trigger the bullwhip effect despite the delays in the goods delivery in the nominal operating conditions in supply chains. However, in networked environments, even the basic configuration triggers the bullwhip effect.

An Item Response Theory to Analyze the Psychological Impacts of Rail-Transport Delay

Questionnaire instruments have been used extensively by researchers in the literature review for evaluation of various aspects of public transportation. Important implications have been derived from those instruments to improve various aspects of the transport. However, it is important that instruments, which are designed to measure various stimuli, meet criteria of reliability to reflect a real impact of the stressors. Particularly, given the diverse range of commuter characteristics considered in this study, it is necessary to ensure that instruments are reliable and accurate. This can be achieved by finding the relationship between the item’s properties and the underlying unobserved trait, being measured. The item response theory (IRT) refers to measurement of an instrument’s reliability by examining the relationship between the unobserved trait and various observed items. In this study, to determine if our instrument suffers from any potentially associated problems, the IRT analysis was conducted. The analysis was employed based on the graded response model (GRM) due to the ordinal nature of the data. Various aspects of the instruments, such as discriminability and informativity of the items were tested. For instance, it was found while the classical test theory (CTT) confirm the reliability of the instrument, IRT highlight some concerns regarding the instrument. Also, the person fit assessment measure, for instance, highlights some concern regarding respondents answering some of the questions due to lack of interest, choosing answers randomly. Not many studies have examined instruments’ reliability in determining the psychological impacts of public transportation on commuters in the way that was performed here.

Controller design by the motion separation method with applying stability criterions for non-linear objects with transport delays

Controllers and feedback are applied for performing many technical tasks, for example, maintaining the desired temperature stabilization in the thermostat and speed electric motor stabilization. Different methods such as the time-scale separation method, the frequency-response design method, and the Ziegler–Nichols method are applied to design controllers. The Ziegler–Nichols method does not provide the required transient process quality. The Smith predictor is sometimes applied to control objects with a transport delay. However, it may be difficult to apply the Smith predictor when a mathematical model is not fully known. There is a paper where the application of the motion separation method with a delay is considered. However, the calculation method proposed in that work requires solving a system of four nonlinear equations for a second-order object. Therefore, in this paper, we investigate the possibility of a simpler method for calculating the controller, namely, the possibility of using the Mikhailov criterion in the synthesis of a controller by the motion separation method for nonlinear objects with a delay. Also, the application of the Nyquist stability criterion with a simpler than the proposed earlier calculation procedure is considered in the paper. The values of the regulator coefficients obtained using the Nyquist criterion and the Mikhailov criterion are compared. The Mikhailov criterion and the Nyquist criterion are applied to estimate the stability of the fast motions subsystem. The derivation of formulas to calculate the parameters of the controller designed by the motion separation method for first-order non-linear objects with transport delays and second-order non-linear objects with transport delays with the use of the Mikhailov criterion is also considered in the paper. Transient processes are studied by numerical simulation. Transient processes plots are also given. The parameters of the controller that are needed to improve the performance of transient processes in the presence of a delay are found. The Peltier element, an aircraft strength test stand, a thermostat, and equipment for metal rolling are non-linear control objects with a transport delay. The Mikhailov hodographs for objects with a transport delay are presented.

Control objects with variable transport delay

Research aim is to analyze a class of automatic control systems at mining and concentrating facilities, where controlling action is the consumption of fuel or substance by a transporting body in order to develop recommendations on stability and control quality improvement. Research methodology consists in working out a model of automatic control system and studying the infl uence of varying transportation delay on the model, which arises in the process of stabilizing the output value of the system of automatic control. The RMS error of output value control was measured on the system’s model when measuring the delay of the main controlling action. Discussion was carried out by the example of the control process where the output value of the control object is regulated by the conveyor which feeds the ore. It has been shown that when changing the controlling action (ore consumption), time the delivery time also changes at the same time. These facilities refer to the facilities with the varying parameter – delay in control; they are poorly explored. It has been shown that control systems like that cannot adequately operate in the general case. One of the main methods of improving the quality of such control systems is to use the Smith predictor. However, in this case the system of automatic control will operate adequately under constant parameters of the control object, which is highly unlikely in the conditions of mining treatment. Delay in such systems is defi nitely associated with the speed of material feed. It has been proposed to automatically change regulator’s settings depending on the speed of the conveyor. Material can be fed using an assembly with constant speed, as an alternative, while the consumption may be carried out in accordance with the variation of the control object output value by a separate feeder